Automobiles utilize safety restraint systems to protect vehicle occupants. Most vehicle safety systems are designed to mitigate potential injuries to occupants during vehicle crashes and, in particular, mitigate injuries to the chest, abdomen and head areas of vehicle occupants. Vehicle safety systems development has progressively targeted new methods for enhanced injury mitigation. For example, restraint systems may include safety devices such as front airbags, side airbags, and seatbelt pretensioners. Presently, restraint systems typically include passive accelerometer-based collision severity sensors, which are used to gather information for control and deployment of the restraints. The collision sensors are typically in the form of solid-state accelerometers that are located in a vehicle compartment, such as in a dashboard, in a tunnel location, behind a bumper, or on a radiator support. The accelerometers are used to detect collision conditions early on in a collision event and provide information related to the collision severity. Various algorithms are then utilized to evaluate the collision conditions and the collision severity for the development of safety systems.
The algorithms utilize accelerometer information, collected early in a collision event and in response to a collision, to determine timing for deployment of restraint systems. It is desirable in the deployment of the restraint systems to prevent inappropriate deployment timing or inadvertent deployment of the restraint systems. Thus, deployment thresholds are often set in response to the type of collision and the associated conditions thereof.
Special collision events such as low speed barrier collisions, pole collisions, and various vehicle-to-vehicle collisions provide the greatest challenges for collision sensor design, and collision type determination. The term “collision type” generally refers to the location on a host vehicle that is involved in the collision and may include other related information. A collision type may for example refer to whether a particular collision is a full-frontal, an oblique, or an offset collision, as well as include information related to relative location, and collision change in velocity of an object of concern.
Sensor and algorithm design criteria of a safety restraint system ensure that the performance of a sensing system satisfy timing requirements for various different collision types and also have the capability of appropriately maintaining safety systems in a deactivated state during non-deployment conditions. It is also desirable to optimize protection for various occupants while reducing restraint-induced injuries such as airbag related injuries. Further, it is desirable to improve restraint performance for a wider range of vehicle occupants such as those in the 5th, 50th, and 95th percentile for vehicle occupants. There thus exists a need for improved methods to intelligently control the direction, localization and areas where the forces of vehicle safety restraints act on various vehicle occupants to enhance occupant safety. In particular, it would be desirable to actively analyze and adapt the occupant-safety restraint interaction during a crash event to improve injury mitigation.